1. Field of the Invention
The present invention relates generally to containers and methods of manufacturing containers.
2. Discussion of the Related Art
Containers are useful and necessary in human society. In modern commerce and applications, they are used in a vast array of applications, some more demanding than others.
To be economically and environmentally efficient, containers (like other manufactured items) need to use a minimum amount of material. Not only does this reduce the waste that results at the end of the container's useful life, it also reduces the costs of materials to manufacture the container, reduces the transportation costs that can be involved in using the container, and provides other benefits. For containers made from plastic or similar materials, the rising costs of materials and the need for ecological responsibility can be substantial.
On the other hand, many or even most containers require some degree of reliable structural integrity. Among other things, they may be stacked three or four (or more) high on pallets for storage and/or transportation, and possibly have other pallets or objects stacked on top of those stacks.
Square, rectangular, or other cornered containers can more efficiently use a given volume of space on a pallet and/or in a warehouse or retail store (as compared to conventional round plastic buckets). They can benefit from the foregoing reduction in material usage, and can provide interesting design and performance challenges as compared to non-cornered containers.
Design and performance characteristics for a container or other product also may be important with respect to material selection. For example, in certain applications, one material may be preferred or even required instead of another (e.g., polypropylene instead of polyethylene) in order to meet the performance criteria (such as withstanding anticipated vertical compression loads or other forces).
In addition, reducing the non-material costs of manufacture also improves the economics and ecological considerations of making and using a given container. For example, to the extent that the energy requirements for making a given container can be reduced, the economic and environmental characteristics of the container and fabrication process are also improved. For applications and processes such as injection molding of plastic containers or other products, a lower injection pressure (to inject the plastic into a mold) can mean that less energy is needed to manufacture that product.
Accordingly, it is desirable to provide methods and apparatus for containers having sufficient strength and durability to withstand heavy loads and predictable storage and handling risks, while reducing costs and usage of materials and providing other benefits.